All types of adjuncts (my conclusion from wikipedia.org):
An adnominal adjunct is an adjunct modifying noun, i.e. it's dependent words in noun phrases (a good boy, the discussion before the game). There is also a noun adjunct – a type of adnominal adjunct - a noun functioning as a pre-modifier in a noun phrase (examinations department).
An adadjectival adjunct is an adjunct modifying adjective, i.e. it's dependent words in adjective phrases (very happy).
An adadverbial adjunct is an adjunct modifying adverb, i.e. it's dependent words in adverbial phrases (too loudly).
An adverbial adjunct is an adjunct modifying verb (She will leave tomorrow / in the morning / after she has had breakfast).
But if we look at the page in wikipedia.org about modifiers and their types, we can see examples absolutely analogous to the examples of the adjuncts above.
Therefore, adjuncts and modifiers are just synonyms. Am I right and if not, then why?